The external appearance of skin is determined by the extracellular matrix (ECM) in the dermal tissue. Collagen accounts for about 70-80% of the proteins present in the ECM. The formation of skin wrinkles is caused by the inhibited production and degradation of collagen induced by aging, UV, etc. In particular, the expression of matrix metalloproteinases such as collagenase leads to wrinkle formation via breakdown of collagen that has been normally produced in skin.
Various substances have been developed and are used to inhibit the reduction of collagen which causes wrinkle formation. Retinoids such as retinol, retinoic acid, etc. exhibit the effect of improving wrinkles (Dermatologic Therapy, 1998, 16, 357-364) and a composition comprising malt extract is used to inhibit collagenase. However, the retinoids are disadvantageous in that they can cause irritation when applied to skin even with a small amount. And, since substances derived from natural products have been mostly used as simple extracts and it is unclear what ingredients of the extracts exhibit the desired effect, it is difficult to continuously maintain and control the activity of the extracts.
Decreased water content in skin often leads cornification caused by skin dryness. Also, it results in loss of skin luster, easy formation of fine wrinkles and early skin aging. Accordingly, skin moisturization is essential for improvement of skin.
The inventors of the present disclosure have found out that a mixture of a oriental herbal medicine processed ginseng extract and a oriental herbal medicine processed green tea extract exhibits very superior synergic effect in prevention of skin wrinkle formation, improvement of wrinkles and moisturization of skin as compared to a mixture of simple ginseng and green tea extracts.